1) Chapter 27: Surah An-Naml (The Ants), verse 61

“Is not He (better than your gods) Who has made the earth as a fixed abode, and has placed rivers in its midst, and has placed firm mountains therein, and has set a barrier between the two seas (of salt and sweet water). Is there any ilah (god) with Allah? Nay, but most of them know not.”

2) Chapter 55: Surah Ar-Rahmaan (The Most Gracious), verses 19 and 20

“He has let loosed the two seas (the salt water and the sweet) meeting together.” “Between them is a barrier which none of them can transgress.”

~~~

Know that Qur’an was complete about 1400 years ago and there was no edition made since then. How could one have known about the fact that salt and sweet waters are separated in the seas at that time? (: (:

Let’s ponder…
   All praises be to Allah.. (:

Peace Be Unto You
Assalaamu’alaikum wr. wb.